Hawaiian Coral Reef Ecosystem a Unique Treasure

By John Roachfor National Geographic News

July 14, 2003

Editor's Note: Jean-Michel Cousteau's Ocean Futures Society is on a film expedition in the remote Northwestern Hawaiian Islands to raise awareness about the need to protect the region's unique biodiversity for future generations. This is the second National Geographic News feature to showcase the islands and the expedition.

For the past 50 million years the Pacific Plate has slowly crept over a stationary plume of magma deep in the Earth's mantle, allowing the formation of a chain of islands that today comprise the most remote, large scale coral reef ecosystem on the planet.

The region, known as the Northwestern Hawaiian Islands, stretches 1,200 miles (1,930 kilometers) towards Asia from the main Hawaiian Islands and is home to a thriving marine ecosystem full of unique, or endemic, species. Many of the corals, fishes, sea birds, and mammals that are found there are found nowhere else in the world.

"You can't go anywhere else in the world and find a large scale coral reef ecosystem as intact as you see in the Northwestern Hawaiian Islands. It makes it really unique," said Dave Gulko, a coral reef ecologist with the Hawaii Department of Land and Natural Resources in Honolulu.

Gulko was one of the primary investigators on a multi-agency and research institution expedition to survey the region in 2000 to determine its management needs. Now, Jean-Michel Cousteau's Ocean Futures Society is on a film expedition in the region to raise awareness about the need to protect it for future generations.

"If protected it would be a major accomplishment on the part of this country to preserve the largest coral reef [system] that exists in the U.S.," said Cousteau in an interview prior to his departure. The region is proposed to become the country's 14th National Marine Sanctuary.

Cousteau and his crew of 22 are currently in the islands, exploring the mid-ocean ecosystem formed millions of years ago and left largely undisturbed by humankind. The adventure can be followed along via the website of the Ocean Futures Society (www.oceanfutures.org).

Island and Reef Formation

The Northwestern Hawaiian Islands are part of the Hawaiian Ridge-Emperor Seamounts chain that extends some 3,700 miles (6,000 kilometers) from the island of Hawaii to the Aleutian Trench off the coast of Siberia, according to Ken Rubin, a geologist at the University of Hawaii in Honolulu.

A stationary plume of magma called a hotspot forms the chain as the Pacific Plate creeps over it in a northwesterly direction at a rate of about 4 inches (10 centimeters) per year.

The hotspot is presently somewhere underneath the vicinity of the southern end of the island of Hawaii, causing molten lava to ooze out of the Kilauea and Mauna Loa volcanoes and the underwater seamount Lo'ihi, which is off the southern end of the island.

"It is believed that the hotspot feeds all three roughly vertically from below but the details of the plumbing and the circumference of the hotspot column as it rises through the mantle to the base of the crust are not well established," said Rubin.